Carefully remove the stones from the Metis® and place in a saucepan with the remaining jam ingredients. Bring to a gentle simmer and leave for about 30 minutes, stirring occasionally. The fruit should have broken down and the jam thickened.
To make the crumble, place the oats, flour, brown sugar, baking powder and salt in a food processor. Blitz for about 10 seconds until it resembles an oat flour.
Add the vegan butter and blitz again until the mixture is combined and starting to clump together.
Grease and line an 8x8 inch baking tin. Place two thirds of the crumble mixture in the tin, using the back of a metal spoon to create an even layer. Put in the oven for 10-12 minutes.
Remove from the oven and when the jam is ready, pour it on top of the crumble. Place the remaining crumble mixture on top, using your fingers.
Put back into the oven for 25-35 minutes until the topping is golden brown.
Leave to cool completely then place in the fridge for a couple of hours. Place onto a chopping board and cut into 16 squares
Serve immediately or keep in the fridge for 2-3 days.